Prototypic and arkypallidal neurons in the dopamine-intact external globus pallidus

A. Abdi, N. Mallet, F. Y. Mohamed, A. Sharott, P. D. Dodson, K. C. Nakamura, S. Suri, S. V. Avery, J. T. Larvin, F. N. Garas, S. N. Garas, F. Vinciati, S. Morin, E. Bezard, J. Baufreton, P. J. Magill
Journal of Neuroscience. 2015-04-29; 35(17): 6667-6688
DOI: 10.1523/JNEUROSCI.4662-14.2015

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1. J Neurosci. 2015 Apr 29;35(17):6667-88. doi: 10.1523/JNEUROSCI.4662-14.2015.

Prototypic and arkypallidal neurons in the dopamine-intact external globus
pallidus.

Abdi A(1), Mallet N(2), Mohamed FY(3), Sharott A(3), Dodson PD(4), Nakamura
KC(3), Suri S(3), Avery SV(3), Larvin JT(3), Garas FN(3), Garas SN(3), Vinciati
F(3), Morin S(1), Bezard E(1), Baufreton J(5), Magill PJ(6).

Author information:
(1)Université de Bordeaux, Institut des Maladies Neurodégénératives, F-33000
Bordeaux, France, Centre National de la Recherche Scientifique Unité Mixte de
Recherche 5293, Institut des Maladies Neurodégénératives, F-33000 Bordeaux,
France.
(2)Université de Bordeaux, Institut des Maladies Neurodégénératives, F-33000
Bordeaux, France, Centre National de la Recherche Scientifique Unité Mixte de
Recherche 5293, Institut des Maladies Neurodégénératives, F-33000 Bordeaux,
France, Medical Research Council Brain Network Dynamics Unit, Department of
Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom, and.
(3)Medical Research Council Brain Network Dynamics Unit, Department of
Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom, and.
(4)Medical Research Council Brain Network Dynamics Unit, Department of
Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom, and Oxford
Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3QX, United Kingdom.
(5)Université de Bordeaux, Institut des Maladies Neurodégénératives, F-33000
Bordeaux, France, Centre National de la Recherche Scientifique Unité Mixte de
Recherche 5293, Institut des Maladies Neurodégénératives, F-33000 Bordeaux,
France, .
(6)Medical Research Council Brain Network Dynamics Unit, Department of
Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom, and Oxford
Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3QX, United Kingdom
.

Studies in dopamine-depleted rats indicate that the external globus pallidus
(GPe) contains two main types of GABAergic projection cell; so-called
« prototypic » and « arkypallidal » neurons. Here, we used correlative anatomical and
electrophysiological approaches in rats to determine whether and how this
dichotomous organization applies to the dopamine-intact GPe. Prototypic neurons
coexpressed the transcription factors Nkx2-1 and Lhx6, comprised approximately
two-thirds of all GPe neurons, and were the major GPe cell type innervating the
subthalamic nucleus (STN). In contrast, arkypallidal neurons expressed the
transcription factor FoxP2, constituted just over one-fourth of GPe neurons, and
innervated the striatum but not STN. In anesthetized dopamine-intact rats,
molecularly identified prototypic neurons fired at relatively high rates and with
high regularity, regardless of brain state (slow-wave activity or spontaneous
activation). On average, arkypallidal neurons fired at lower rates and
regularities than prototypic neurons, and the two cell types could be further
distinguished by the temporal coupling of their firing to ongoing cortical
oscillations. Complementing the activity differences observed in vivo, the
autonomous firing of identified arkypallidal neurons in vitro was slower and more
variable than that of prototypic neurons, which tallied with arkypallidal neurons
displaying lower amplitudes of a « persistent » sodium current important for such
pacemaking. Arkypallidal neurons also exhibited weaker driven and rebound firing
compared with prototypic neurons. In conclusion, our data support the concept
that a dichotomous functional organization, as actioned by arkypallidal and
prototypic neurons with specialized molecular, structural, and physiological
properties, is fundamental to the operations of the dopamine-intact GPe.

Copyright © 2015 Abdi et al.

DOI: 10.1523/JNEUROSCI.4662-14.2015
PMCID: PMC4412890
PMID: 25926446 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus